In recent years, hybrid electric vehicles and electric vehicles have been getting popular. Each of these vehicles has a less or no amount of exhaust heat from an engine compared with other automobiles. Therefore, a vehicle interior of each of these vehicles is not fully heated with only exhaust heat from the engine.
A seat heater for directly heating a seating person has now been focused on. In order to fully heat a vehicle interior of a vehicle having a smaller amount of exhaust heat from an engine, a seat heater that outputs a larger amount of heat has been demanded.
A temperature of a seat heater having a higher output rises faster than a temperature of a conventional seat heater. To heat a protection device that stops the seat heater in an event of emergency along with this rise in temperature of the seating heater, an amount of heat output from a heater for the protection device should be increased. Thus, it has been proposed that a heater for a protection device covers a pair of portions facing each other of the protection device. By covering the pair of portions, heating of the protection device is facilitated. As a result, a temperature that is higher than a temperature at which the seat heater normally operates can be set as an operating temperature of the protection device (see International Patent Publication No. 2014/017078).